Ecosystems at the End of the Earth

Kelsey Simpkins

2 years ago

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The summer season has arrived in Antarctica. And with it, a team of scientists from the University of Colorado, who have travelled halfway around the world to study the smallest of organisms in the harshest of environments.

For the next few months, these researchers will be living at the bottom of the world in the Dry Valleys of Antarctica to inspect and experiment with living black gunk in holes that cover glaciers like acne. In each of these cryoconite holes an isolated world thrives, full of sediment, water, air, ice—and microbes.

By studying these microbial ecosystems invisible to the eye, the scientists hope to gain greater insight into how the more complex and visible world around us actually works, from the bacteria in our guts to the creation of new species.

“There are some general ecological principles that people have been trying to untangle for decades,” said Dorota Porazinska, one of the scientists currently working in Antarctica. And cryoconite holes may help connect the dots.

But why use microbes, let alone ones at the end of the earth, to answer these long-standing ecological questions?

“Microbes are everything on the planet,” according to Jack Darcy, another member of the team. “They’re everywhere, they’re all over you, they’re all over inside you.”

There are actually more microbial cells in your body than your cells, according to Rebecca Safran, a biologist at the University of Colorado Boulder.

In addition to permeating life on Earth, microbes are especially helpful in studies because of their short life spans — only days long. This allows scientists to fast-forward ecological processes that could otherwise take years to observe.

Yet until recently, soil microbes were mostly a mystery: difficult to identify and almost impossible to grow in a laboratory. But with recent advances in DNA technology, scientists have seen a whole new side of life brought to light in the past decade.

So like a study with laboratory mice that extrapolates its results to humans, these researchers aim to apply what they find out about wild microbes living on glaciers to our bodies and the world around us.

Pacifica Sommers hopes to test several hypotheses about ecosystems on cryoconite holes this year in Antarctica, including one she calls “finder’s keeper’s,” which examines how the first organisms to arrive in a location might change something in that environment.

In a larger ecosystem such as a forest, the landscape can change drastically with the presence of a beaver building dams. Compared to an ecosystem with no beavers, “you might get radically different plant communities,” Sommers said. But beavers — and big landscapes — don’t make very good test subjects.

The soils in Antarctica support less than 10 microbial species, so the Dry Valleys provide a smaller and simplified ecosystem where Sommers can test her ideas on ecosystems within cryoconite holes.

Cryoconite holes form as wind blows dust and dirt from surrounding environments onto the surface of a glacier. Absorbing more sunlight than the reflective ice around it, this dark sediment melts a hole into the ice, sometimes reaching more than a foot deep. And they can cover up to 15 percent of a glacier’s surface, like sprinkled pepper.

But the best part for Sommers is that these holes freeze over, sealing themselves off from outside influences and forming their own little worlds inside. She and the team will hike up onto the glaciers every day to create and monitor their own man-made cryoconite holes, filled with communities of microbes they introduce into them in different orders.

These microbial communities are known as mats, made up of biodiverse material from streams conveniently categorized by the colors they look like: red, orange, green and black.

Sommers wants to know how the communities will react if black, for example, is introduced before orange and vice versa. Will green and red coexist? Does orange eliminate red?

These questions may seem simplistic, but this research has broad implications.

Whether microbes or large animals, according to Safran, these ecological processes are very similar in terms of what that governs them. Scientists see them “over and over again in different contexts.”

Safran’s main research is understanding how new species form, with barn swallow populations. But she also studies microbial communities within these birds.

“What’s really been fun is adding the layer of microbial communities to what the swallows have been doing,” she said. Her research has found that these communities can be essential for mediating health outcomes and disease risk. “It’s this revolutionary idea, that this diversity that we ourselves harbor, can have really profound influences on our own health outcomes.”

While the details always matter in ecology and evolution and results will differ in different situations and locations, according to Safran, the general principles and processes usually support the same hypotheses.

Down in Antarctica, the team of scientists is hoping for good results from their newly begun microbial research. And in this wide open field of scientific discovery, they are humble about their efforts to understand these ubiquitous organisms.

“You can’t really live without them,” said Steve Schmidt, another member of the Antarctic team. “They run the planet.”